window.onload = function(){
    document.getElementById("btn1").ondblclick=function(){
        alert('11111111')
    }

    document.getElementById("btn2").onclick=function(){
        alert('11111111')
    }

    document.getElementById("btn3").onmouseover=function(){
        alert('11111111')
    }

    document.getElementById("btn4").onkeydown=function(){
        alert('按下键盘')
    }

    document.getElementById("btn5").onkeyup=function(){
        alert('松开键盘')
    }

    document.getElementById("btn6").ondblclick=function(){
        alert('11111111')
    }
    
    document.getElementById("btn7").ondblclick=function(){
        alert('11111111')
    }
}

